1. Field of the Invention
The invention relates to a decoding apparatus for audio signals and the method thereof, especially to a decoding apparatus for multiple audio signals and the method thereof.
2. Description of the Prior Art
According to the prior art, the audio signals applied in televisions and video systems include a lot of different coding/decoding standards, e.g. the broadcast television system committee (BTSC) standard applied in America, the FM/FM standard applied in Japan, the A2 standard, and so on.
Please refer to FIG. 1. FIG. 1 is a schematic diagram of a decoding apparatus 10 for audio signals in compliance with the BTSC standard according to the prior art. The decoding apparatus 10 for audio signals in compliance with the BTSC standard according to the prior art includes an RF tuner 12, an A/D converter 14, a processor 16, and a digital BTSC decoder 18.
The RF tuner 12 is used for receiving a BTSC analog audio signal 20 and converting the BTSC analog audio signal 20 to a BTSC analog sound intercarrier frequency (SIF) signal 22. The A/D converter 14 is used for converting the BTSC analog sound intercarrier frequency (SIF) signal 22 to a BTSC digital SIF signal 24. The processor 16 is used for calculating to obtain a multi-channel television sound (MTS) demodulated signal 26 according to the inputted BTSC digital SIF signal 24. The MTS demodulated signal 26 includes a summed L+R audio output signal and a difference L−R audio output signal 30. The digital BTSC decoder 18 is used for decoding the MTS demodulated signal 26 and for generating a summed L+R audio output signal 28 and a difference L−R audio output signal 30 according to the demodulation/decoding procedure of the BTSC standard.
According to the prior art, each of the decoding apparatus for audio signals applied in televisions and video systems is in compliance with each of the different coding/decoding standards respectively, so that it is inconvenient to develop different circuit designs for all the different audio signals. Therefore, it is necessary to provide a decoding apparatus for multiple audio signal standards and method thereof to improve flexibility of circuit design for decoding audio signals.